The invention relates to a vehicle with at least two single-wheel drive units and a method for controlling the single-wheel drive units.
In vehicles with exclusive electromotive drive or also in hybrid vehicles with an internal combustion engine and with electromotive drive, drive systems are known which at least at one vehicle axle have two electric machines which are controllable independent of one another and which respectively drive one drive wheel at the left and the right vehicle side.
From DE 40 11 291 A1 a vehicle of the generic type is known which has two drive-electromotors at the front axle as well as at the rear axle, one of which motors is provided for driving a drive wheel on the left side of the vehicle and the other one is provided for driving a drive wheel on the right side of the vehicle. The drive-electromotors are controllable by means of an electronic control device which determines a target torque in response to a driver request. In a torque distribution unit the target torque is divided into a first target torque for the first drive unit and a second target torque for the second drive unit.
The invention is based on the problem that due to manufacturing and component tolerances the drive electromotors can have a slightly different response characteristic at a same target torque. This is exacerbated by ageing over the life cycle of the vehicle. The difference in torque between the two drive-electromotors resulting from this circumstance causes the vehicle to be constantly subjected during driving to a yawing moment which acts about the vertical axis of the vehicle. In the case of a chassis control system integrated in the vehicle which enables an individual distribution of the drive torque in dependence on the driving situation, the chassis control system would thus also be activated when the vehicle drives straight ahead. In contrast, in a vehicle without chassis control system, a driver would have to constantly steer against the yawing torque generated by the drive units.